The other day I read an article in the New Scientist (#2879) about an alternative bio-fuel source. Current bio-fuel sources such as sugar-cane and corn are being grown on agricultural land causing concern about possible future food shortages.

This new possibility is the use of micro-algae to produce bio-fuel. Some algae are amongst the fastest growing plants while others can produce between 18700 and 46750 litres of oil per hectare annually. This is about 100 times more than soy-beans at 468 litres.

An added bonus is that freshwater algae can be cultivated in waste water and marine algae in a blend of waste water and seawater. The algae not only multiply but also clean the water while doing so, removing pollutants and nutrients such as fertiliser. This also means that there is no need to use precious fresh water to grow the algae. According to the UN, 80% of waste water (about 1200 cubic kilometres) is currently left untreated so there is already a suitable supply of nutrient-rich water available.

There are a few problems that need ironing out. Firstly, there are few species of domesticated micro-algae, therefore there is not enough data available to make plans to grow it commercially, such as how much algae needs to be grown to meet the demand. Secondly, space would have to be found to farm the organism. Algae need light and must not get too hot.

The current thought of bio-fuels guru Jonathan Trent is to utilise non-arable land close to waste-water treatment plants or to site installations off-shore, running waste water through plastic tubes that would float on the ocean in protected bays. He calls this system OMEGA - Offshore Membrane Enclosures for Growing Algae.

He has more ideas for this system involving using forward osmosis to prepare the algae for harvesting as well as cleaning the water - he also envisages the pipes forming a type of artificial reef. The system is environmentally sound as, should any freshwater algae escape, they would immediately die in the salt water, preventing invasive species from contaminating the ecosystem.

Potential sites include places like Saudi Arabia, New Zealand and Australia. All that is required is a commitment from someone to set up a demonstration site. And of course - the funds.

Personally I feel that this is major breakthrough, a possibility that would solve many problems. Hopefully governments will feel the same way and pledge money to support this cutting-edge idea.